Table 1.
Summary of within-lineage size trends across mass extinction intervals in invertebrate species or genera.
Figure 1.
Locality maps and stratigraphical logs for the two study regions, Denmark and the southeastern USA.
Stratigraphical formations and members are shown to highlight the units from which specimens were collected for analysis. Global palaeomap adapted from: http://scotese.com/K/t.htm.
Figure 2.
SEM images of species used in this study.
Left-hand column shows Maastrichtian specimens, right-hand column Danian specimens. Rows are congeneric (or conspecific) pairs. Examples of maximum zooid length (ZL) and maximum zooid width (ZW) measurements are shown on the Maastrichtian specimens. A. Balantiostoma nomas (Shaw, 1967); B. Balantiostoma midwayanica (Canu and Bassler, 1920); C. Tricephalopora larwoodi (Shaw, 1967); D. Tricephalopora levigatum (Canu and Bassler, 1920); E. Pliophloea subcornuta (Berthelsen, 1962); F. Pliophloea subcornuta; G. Stichomicropora sp. 1; H. Stichomicropora sp. 2.
Table 2.
Number of (A) colonies measured, (B) zooids measured and (C) species, from which zooids were measured in the USA.
Table 3.
Number of (A) colonies measured, (B) zooids measured and (C) species, from which zooids were measured in Denmark.
Figure 3.
Mean, minimum and maximum colony size for taxa.
Colony sizes of taxa analysed from the Maastrichtian Prairie Bluff Chalk/Højerup Member (K) and the Paleogene Clayton Formation/Korsnæb Member (Pg). The total number of colonies measured is indicated above each data point. p>0.05 across the K–Pg boundary for each pair.
Table 4.
Nested ANOVA results for colony area.
Figure 4.
Mean zooid width and length for all colonies.
Balantiostoma: K = Cretaceous Prairie Bluff Chalk (Balantiostoma nomas); Pg = Paleogene Clayton Formation (B. midwayanica). Tricephalopora:K = Cretaceous Prairie Bluff Chalk (Tricephalopora larwoodi); Pg = Paleogene Clayton Formation (T. levigatum). Pliophloea:K = Cretaceous Højerup Member; Pg = Paleogene Korsnæb Member. Stichomicropora: K = Cretaceous Højerup Member; Pg = Paleogene Korsnæb Member. Error bars show minimum and maximum width and length measured for each colony.
Table 5.
Nested ANOVA results for zooid length.
Table 6.
Nested ANOVA results for zooid width.
Table 7.
Nested ANOVA results for zooid area.
Figure 5.
Mean zooid length of all species present in the studied samples.
Histograms showing the lengths of zooids from the Maastrichtian Prairie Bluff Chalk/Højerup Member (K) and the Paleogene Clayton Formation/Korsnæb Member (Pg). The total number of species is indicated. p>0.05 across the K–Pg boundary in the USA and Denmark in a comparison of overall bryozoan zooid size.
Table 8.
Nested ANOVA results for zooid length of all species.